HX711 pull measure

[FPChris]

Hello,

I'm trying to make a pull measuring device for archery with a single cell like the type usually
in 4s in bathroom scales. But I want to read 0% at relaxed and 100% at full draw.

I don't really care about the weight itself just the range. Is there a way to have scale.read()
return 0 to 100 range?

I have it hooked up like the attached imaged and I'm using the HX711 Arduino Library.

Thanks

[MarkT]

This might be useful: map() - Arduino Reference

[Ron_Blain]

What you have pictured is a compression type load cell and yes, the type used in a bathroom or similar scale. If you want to measure the draw force of a bow you will likely want a tension type load cell rather than a compression type. Basic load cells for measuring force generally come in two basic flavors, Tension and Compression. They do make draw weight scales for bows. However, you can roll your own. The standard for determining their draw weight is taken at 28 inches of draw length.

A Google of Tension Load Cell will bring up plenty including several cheap / inexpensive off the boat versions like this one which includes everything needed less the uC (Arduino). You can calibrate the end result in Lbs or Kg depending on what you want. The better quality S-Beam load cells come with a higher cost so it all depends on what you want.

Ron